Indicating ringing-key.



W/f/vesses:

E. B. CRAFT.

INDIOATING RINGING KEY.

APPLICATION FILED 0014,1010.

Patented Feb. 3, 1914.

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COLUMBIA PLANOGRAPH COHWASHINGTON, u. c.

UNITED STATES PATENT OFFICE.

EDWARD B. CRAFT, OF HACKENSACK, NEW JERSEY, ASSIGNOR '10 WESTERN;ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

INDICATING RING-INGeKEY.

Specification of Letters Patent.

Patented Feb. 3,1914.

Application filed October 4, 1910. Serial No. 585,292.

To all whom it may concern Be it known that I, EDWARD B. CRAFT, citizen of the United States, residing at Hackensack, in the county of-Bergen and State of New Jersey, have invented a certain new and useful Improvement in Indi cating Ringing-Keys, of which the follow ing is in full, clear, concise, and exact description.

This invention relates to switching apparatus for electrical circuits.

The object of the invention is to supply a series of keys of similar appearance, construction and function, so arranged that when one of the series is operated it will hold a determined position that distinguishes it from the others of the series, the key last operated being the one that is thus distinguished.

The invention is useful in the construction of a party line calling key for a telephone exchange where a plurality of such apparently identical keys are arranged in a plate, the plate or base being fixed to the operatons switchboard. In such cases the operator is able to call any one of a number of stations on one circuit, using different characteristics of current; in this case it is desirable and useful to be able to determine which key of the series was last operated. Apparatus of this class has been known and used prior to this invention and several specific forms of apparatus have been described.

This invention consists in arrangin a series of keys in a line, depressing any :ey to signal and leaving such key elevated above the others of the series to identify it as the one last operated; this is done by depressing all keys and automatically retaining in a depressed position all keys except the key last operated, so that said last operated key is elevated or projected out of the normal operating plane or position of the others until another key is operated.

The accompanying drawings illustrate the invention Figure 1 is a side elevation with a portion removed to show the operation of the holding pawls; Fig. 2 is a section of the same from the opposite side; Fig. 3 is an end elevation showing a supplemental switch; Fig. 4. is a detail showing the sliding box with its retracting spring and its relation to the sliding rod and the device forming a mechanical connection between the keys or plungers; section taken on line it-A, Fig. 1.; Fig. 5 is a section on line 6-6 looking in the direction of the arrows with the key or plunger depressed; Fig. 6 is a similar section with the key or plunger elevated; Fig. 7 shows a key or plunger, the sliding box and the insulating contact which engages the electrical contacts; Fig. 8 shows the pivoted, common mechanical connection between the keys or plungers and the insulating con tact for operating the supplemental switch; Fig. 9 shows an arrangement of a circuit in connection with --which the key is useful in a telephone exchange.

The party line calling key embodying this invention, as shown in the drawings, includes a base plate a which is preferably sunk flush with the surface of the key shelf of the switchboard. To the plate a is attached, by means of screws 2A, 24:,a frame composed of horizontal members 21 and 23 and vertical members 20 and 22. A guide member 9 having an upturned edge 64 is mounted upon the vertical frame members 20 and 22 intermediate the horizontal frame members 21 and 23. The base plate a=, frame member 23 and the guide member 9 are provided with openings at points in the same vertical line to receive reciprocating plungers or rods 9 Mounted upon the horizontal frame member 21 are blocks 25, 25 each having a passage therein in which the lower ends of the plungers 1" enter. A rocking bar at is pivoted at t-ft, 14: to the vertical frame members 20 and 22 and carries a series of fingers 12, 42, one corresponding to each plunger. Formed integrally with the rocking bar on is a projection 15 carrying at its end an insulating contact 4:6 which operates electrical contacts 1, 2, 3, 4 and 5 secured to the vertical frame member 22 by means of platesLS and 49.

A finger contact 0 of insulating material is secured to the upper end of each plunger 1". The lower end of each plunger is encircled with a spiral spring 26, one end, of which rests against the block 25 and the other end against a shoulder 10 of the plunger, and tends to maintain the plunger in an elevated position. A box I) is slidably mounted upon each of the plungers. The upper portion of one side of the box is slotted, as at s, and a pin 34 carried by the plunger 0' is adapted to move therein. Each plunger 7* is encircled with a second spiral spring 27, the

lower end of which rests against guide member g and the upper end thereof against the box Z), tending to hold said box in an ele vated position. A pawl 79 having a hook 51 on one end thereof and projections 61 and 62 on the other end thereof is pivoted at 33 to each box Z) and is adapted to rotate about its pivot point to engage and disengage pin 34. A lug 41 is formed integrally with the top portion of the box Z) and is adapted to engage one of the fingers 42. Each plunger r carries a second pin 40 which, during the upward movement of the plunger, is adapt ed to engage the finger 42 and to return the rocking bar we to its normal position, and during the downward movement of the operated plunger is adapted to be engaged by the finger 42 corresponding to the last previously operated plunger and lower it to the same horizontal plane in which the unoperated plungers are resting.

The normal position of the key is as shown in Fig. 1; that is, three of the plungers are located in their normal position of rest and the fourth, the last one operated, is elevated above the horizontal plane of the others in its indicating position. Assuming now that any one of the three plungers which are in the same horizontal plane is operated or depressed, the pin 34 is moved downwardly and strikes the bottom of the slot 8 whereupon the box 5 is moved downwardly and the lug 41 thereof engages and depresses its corresponding finger 42. Since all of the fingers 42, 42 are integral with the rock ing bar m, the downward movement of one of these fingers likewise causes the downward movement of all. Therefore, the finger 42, corresponding to the plunger which is elevated, engages the pin 40 thereof and causes a downward movement of said plunger. The end of the finger 42, corresponding to said elevated plunger, engages the projection 61 of its pawl 79, rotating said pawl about its pivot point 33, thereby causing the hook 51 to engage the pin 34 and lock said plunger in its normal position of rest. At the same time, the fingers 42, corresponding to the remaining two plungers which are in their normal position of rest, engage the projections 61 of their respective pawls p and maintain the hooks 51 and the pins 34 in engagement. Since the pawl 79 is mounted upon the box 6, it likewise has a downward movement with the plunger disengagement of the hook 51 and the pin 34. Upon the release of this operated plunger it is elevated to its indicating position due to the action of the spiral spring 27, while the other three plungers of the series are retained in their normal position of rest due to the hooks 51 and the pins 34 being in engagement. During the upward movement of the operated plunger, its pin 40 engages the finger 42 and moves the rocking bar on and all of the fingers 42 to their normal position.

In F ig. 9 the five electrical contacts, 1, 2, 3, 4 and 5 are represented. There are also represented at w in this figure, the four contacts which are operated by the four plungers. The operation of the contacts by the plungers and the association of the contacts with an operators connecting cords and plugs are considered so obvious as to require no detailed description.

What I claim is:

1. In a switching apparatus in combination, a series of contacts, a series of actuating devices for said contacts, and means operating automatically upon the release of one of said actuating devices to cause it to project out of the normal operating plane of the remainder of said actuating devices, and upon the operation of a second of said actuating devices to restore said first mentioned actuating device to normal position and retain said second actuating device in a projecting position.

2. In a party line calling key in combination, a series of contacts, a series of sub stantially identical actuating devices having two positions, one a normal position of rest and the other a contrasting elevated indicating position, means actuated upon the operation of any one of said devices for maintain ing the remaining devices of said series in said normal position of rest, and means operative upon the release of said operated device for elevating said device to said indicating position.

3. A switching apparatus consisting of the combination of a series of contacts, a series of actuating devices, one for each pair of contacts, a normal position of rest for said actuating devices and means for auto matically retaining the last operated device in an elevated position with respect to said normal position.

4. A switching apparatus consisting of the combination of a series of electrical contacts, a series of actuating devices, one for each pair of contacts, means for retaining said devices in a normal position of rest, and means for automatically moving the last op erated device into an elevated position and retaining it in said position after its ope 2 tion and release and until another device is j operated. about its pivot point 33 and causing the 5. In a switching apparatus the combina- 3 tion of a series of electrical contacts, a series of substantially identical operating devices, one for each pair of contacts, and means actuated upon the operation of any one of said devices for retaining said devices in a normal position with the last operated device elevated above the normal plane of the others.

6. In a switching apparatus the combination of a series of electrical contacts, a series of substantially identical operating devices therefor, a holding pawl for each operating device, and means for automatically causing said pawls to engage and hold all but one of said operating devices in a depressed p0- sition.

7. In a switching apparatus the combination of a series of electrical contacts, a series of operating devices, one for each pair of contacts, a retracting device for each operating device, a holding pawl for each operating device, and means actuated upon the operation of any one of said operating devices for automatically engaging said pawls with all of said operating devices except that last operated.

In witness whereof, I hereunto subscribe my name this 30th day of September, A. D.,

EDWARD B. CRAFT. lVitnesses IRVING MACDONALD, MoRGAN VASHBURN, Jr.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Paton. Washington, D. C. 

